This invention includes an alternate embodiment of a high-pressure fuel pump disclosed in, and this patent application incorporates by reference all material contained in, allowed U.S. Pat. application Ser. No. 07/553,523, titled Common Rail Fuel Injection System, filed Jul. 16, 1990, now U.S. Pat. No. 5,133,645, issued Jul. 28, 1992. Embodiments of the apparatus disclosed and claimed in the referenced patent application constitute certain of the elements of the combination of the present application.
Practically all fuel systems for diesel engines employ high-pressure pumps, the output volumes of which are made variable by varying the effective displacements of the pumps. Injection pressures of these systems are generally dependent on speed and fuel output. At lower engine speeds and fuel outputs injection pressure falls off, producing less than an optimum fuel injection process for good combustion.